{smcl}
{* 07jun2006}{...}
{cmd:help mata mm_nobs()}
{hline}

{title:Title}

{p 4 10 2}
{bf:mm_nobs() -- number of observations}


{title:Syntax}

{p 8 23 2}
{it:real scalar}
{cmd:mm_nobs(}{it:transmorphic matrix X}{cmd:,} {it:real colvector w}{cmd:)}


{title:Description}

{pstd}
{cmd:mm_nobs()} determines the number of observations
from given data and weights. Essentially, {cmd:mm_nobs()} is a
shortcut to

      {com}rows(w)==1 ? rows(X)*w : colsum(w){txt}


{title:Remarks}

{pstd}None.


{title:Conformability}

    {cmd:mm_nobs(}{it:X}{cmd:)}
            {it:X}:  {it:r x c}
            {it:w}:  {it:r x 1} or 1 {it:x} 1
       {it:result}:  1 {it:x} 1


{title:Diagnostics}

{pstd}{it:w} should be non-missing and non-negative.


{title:Source code}

{pstd}
{help moremata_source##mm_nobs:mm_nobs.mata}


{title:Author}

{pstd} Ben Jann, University of Bern, jann@soz.unibe.ch


{title:Also see}

{psee}
Online:  help for
{bf:{help moremata}}
{p_end}
